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The area of a circle is increased by 22 sq cm when its radius is increased by 1 cm. Find the original radius of the Circle.

A) 6 cm
B) 3.2 cm
C) 3 cm
D) 3.5 cm

Correct Answer:



C) 3 cm

Description for Correct answer:

Let original radius be r.

Then, according to the question,

\( \Large \pi (r+1)^{2}-\pi r^{2} \)=22

=> \( \Large \pi\times [(r+1)^{2}-r^{2}] \)=22

=> \( \Large \frac{22}{7}\times (r+1+r)(r+1-r) \)=22

=> 2r+1=7 => 2r=6

r=\( \Large \frac{6}{2} \)=3 cm

Part of solved Area and perimeter questions and answers : >> Elementary Mathematics >> Area and perimeter

Comments

Similar Questions

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